Most likely the origin of Mastin Espańol was brought to Spain by the Phoeniciers and Greeks about 2000 years ago.
The Mastín is regarded as Spain's national dog breed, and it can be traced back to 800 BC. The first written evidence of the breed is in the 1200's, where it is mentioned as a guard-dog of livestock.
In the Middle Ages, the Christians in the north and the Moslems in the south of the Iberian peninsula were fighting against each other for the control of the land that would one day become known as Espana. In the Christian kingdoms, the business of wool and lambs was the livelihood of the people.
At that time there existed two hegemonic kingdoms in the yet unborn Spain, Castilla and Aragon. In these kingdoms,each having a very different way of life,two breeds of dogs were born . In the wide and flat Castilla, the Mastin Espanol (Spanish Mastiff); in the heterogeneous and abrupt Aragon, the Mastin del Pirineo (Pyrenean Mastiff).
During the Middle and early Modern Ages the Spanish economy was based on the wool trade.
Since the 12th Century, wool production increased continuously both in overall volume and in quality, thanks to a new breed of sheep called merino. The Aristocracy, the main owner of the flocks, developed a union called 'The Mesta' - founded in 1273 and still operating at the beginning of the 19th Century - to defend shepherds and wool producers. Enormous flocks of merino sheep spent their winter in the warm south of Spain, migrating to the mountains in the North at the beginning of the summer. This was an event on an enormous scale and distance (up to 850km). In the year 1526 no less than 3.453.168 sheep were involved. Excluding approx. 40.000 shepherds and no less than 18.000 Spanish Mastiff for protection!. These frugal, independent dogs had a good coat to cope with extreme weather conditions, and they were capable of organizing an effective defense against predators and big enough to successfully fend off wolves.
Around the 18th century the Mestas became smaller and smaller. And the last Mestas were cancelled in 1936-1939 because of the Spanish civil war. Their numbers dropped dramatically and with no main purpose left the breed to became rare.
In 1946, the Spanish Mastiff was reconigized and approved by the F.C.I. but the breed was on the way to becoming extinct. Beginning around 1980, a new standard was approved and a great effort was put forth by breeders to increase the size and stamina back to the original size and strength.